A green approach to the facile synthesis of colloidal platinum nanoparticles by Preyssler polyoxometalate

In the present study, platinum nanoparticles were synthesized through an effective, facile and green method using H14[NaP5W30O110], a Preyssler-structured polyoxometalate, under UV light irradiation. Preyssler plays the roles of photocatalyst, reducing agent and stabilizer in the synthesis of Pt nanoparticles. The effect of different parameters, i.e. time, propan-2-ol volume, pH, molar ratio of Preyssler to Pt ions ([Preyssler]/[Pt4+]) and temperature on the size of prepared nanoparticles were investigated. Under different conditions, platinum nanoparticles with minimum size of 13 nm were ultimately obtained. The nanoparticles were characterized by UV/Vis spectroscopy, particle size distribution, transmission electron microscopy and electron diffraction techniques. The results showed that the photocatalytic behavior of Preyssler was a propulsion factor in reducing the Pt4+ ions. The resultant NPs are covered with a Preyssler layer which contributes to the stabilization of NPs. It was shown that the subsequent increasing of NP size can be on account of partly increasing rate of NP growth compared to nucleation. Moreover, the stability of obtained nanoparticles was inspected.